Rotating Retractable Writing Instrument

ABSTRACT

The present invention relates to a rotating retractable writing instrument, which is constituted in a simpler way and can thrust a mouthpiece and a writing core element smoothly to positions ready for writing. The writing instrument by the present invention comprises a rear outer cylinder  2 , an inner sheath  4  unrotatably accommodated in the rear outer cylinder  2 , a front outer cylinder  10  from which a mouthpiece  12  and a writing core element  13  can be thrust. A protrusion  45  for restraining rotating range, a refill sliding cam  42  and a mouthpiece sliding cam  43  are formed in the inner sheath  4 . A refill sliding element  6  and a mouthpiece sliding element  7  are accommodated in the inner sheath  4 . The mouthpiece sliding element  7  is connected to the refill sliding element  6 . Further a connecting element  9  is connected to the inner sheath  4 . In the writing instrument constituted in the above-mentioned way, when the rear outer cylinder  2  is rotated in one direction relative to the connecting element  9 , the mouthpiece and the writing core element are thrust out of an opening of the front outer cylinder  10 . When the rear outer cylinder is further rotated, a tip of the writing core element is thrust out of an opening on a front face of the mouthpiece.

FIELD OF INVENTION

The present invention relates to a writing instrument, particularlyrelates to a rotating retractable writing instrument which can thrust amouthpiece and a writing core element to positions ready for writing.

RELATED BACKGROUND ARTS

So-called rotating retractable typed writing instrument comprising arear outer cylinder and a front outer cylinder has been known. When thetwo cylinders are relatively rotated each other, a writing core elementof the writing instrument can be thrust out of the main body of thewriting instrument.

Since the writing core element of such writing instrument can be held inthe main body when the writing instrument is not in use, the writinginstrument can be accommodated in a suit pocked or the like for carryingwithout contaminating the suit with ink.

In such writing instrument, although the writing core element can beheld in the main body, a mouthpiece of the writing instrument is notheld in the main body. Consequently, there is a possibility that themouthpiece might scratch the suit with its sharp tip. Also there isanother possibility that the mouthpiece sticks into and hurts a humanbody, when the mouthpiece is pressed by an external force. There is afurther possibility that the mouthpiece is deformed by an externalimpact.

In order to avoid the above-mentioned possibilities, a rotatingretractable writing instrument which can held the mouthpiece as well asthe writing core element in the main body is proposed (see, for example,Japanese utility model laid open No. 7-32133). The writing instrument isarranged such that when the rear outer cylinder is kept being rotated inone direction relatively to the front outer cylinder, at first themouthpiece is protruded from the main body and then the writing core isprotruded from the mouthpiece by a further rotation. And the rear outercylinder is kept being rotated in the reverse direction, at first thewriting core element is held in the mouthpiece and then the mouth pieceis held in the main body by a further rotation.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The above-mentioned example of the writing instruments is constituted asfollows.

In a state where the mouthpiece is moved backward from an opening of thefront outer cylinder and the writing core element is moved backward froman opening of the mouthpiece, when the rear outer cylinder is rotated inone direction relatively to the front outer cylinder, a protrusion on anouter face of an inner sleeve unit is moved forward along a screw grooveformed on an inner face of a thrusting pipe which constitutes anintermediate sleeve unit, and as a result the mouthpiece is protrudedfrom the main body.

In a state where the mouthpiece is protruded, the protrusion of theinner sleeve unit is at a pushed-out position from the front end of thescrew groove. Just before the mouthpiece is protruded from the mainbody, a protrusion of a connecting element is fitted to the most rearend of the screw groove on the inner face of the thrusting pipe. Whenthe rear outer cylinder is further rotated, the protrusion of theconnecting element is moved forward along the screw groove so that thewriting core element is protruded from the mouthpiece.

In the conventional writing instrument explained above, in a state wherethe protrusion of the inner sleeve unit is pushed out of the screwgroove, but before the protrusion of the connecting element is connectedto the screw groove, a position of the inner sleeve unit in theintermediate sleeve unit and a position of the connecting element in anaxial direction of the main body are restrained by a compressed coilspring for pressing the protrusion of the inner sleeve unit backward andby a compressed coil spring for pressing the connecting elementbackward.

Consequently, in order to carry out two steps smoothly such that aproceeding step for pushing out the protrusion of the inner sleeve unitfrom the front end of the screw groove is smoothly led to a succeedingstep for connecting the connecting element to the screw groove, therearises a problem to adjust a relative balance with good precisionbetween the compressed coil spring for pressing the protrusion of theinner sleeve unit and the compressed coil spring for pressing theconnecting element.

Sometimes the relative balance between the two coil springs is changedwhen the writing instrument is successively used, so that there isanother problem that the mouthpiece and the writing core element cannotbe thrust to positions ready for writing.

The present invention is carried out in view of the above-mentionedproblems in order to provide a rotating retractable writing instrument,which is constituted in a simpler way and can thrust a mouthpiece and awriting core element smoothly to positions ready for writing.

Means to Solve the Problems

The above-mentioned objective by the present invention is attained bythe following technical arrangements.

(1) A rotating retractable writing instrument comprising: a rear outercylinder with an open front face; an inner sheath unrotatablyaccommodated in the rear outer cylinder; and a front outer cylinder withopen faces on both ends, wherein: a mouthpiece and a writing coreelement can be thrust out of an opening formed on the front face of thefront outer cylinder, the writing instrument further comprising: aprotrusion for restraining rotating range arranged on a front end faceof the inner sheath; and a refill sliding cam and a mouthpiece slidingcam formed on an inner face of the inner sheath, the writing instrumentfurther comprising: a refill sliding element and a mouthpiece slidingelement accommodated in the inner sheath slidably in an axial directionand unmovably in a radial direction; and protruded portions for slidingformed respectively on outer faces of the refill sliding element and themouthpiece sliding element; wherein: the protruded portions for slidingare respectively fitted to the refill sliding cam and the mouthpiecesliding cam; and the mouthpiece sliding element is slidably andunrotatably connected to the refill sliding element, the writinginstrument further comprising: a connecting element connected to theinner sheath rotatably and unmovably in the axial direction; and arotating position restraining member arranged on an outer face of theconnecting element for restraining a rotation of the inner sheath;wherein: the mouthpiece sliding element is slidably fitted to theconnecting element, wherein: when the rear outer cylinder is rotated inone direction relative to the connecting element, the inner sheath isrotated in the same direction together with the rear outer cylinder sothat the mouthpiece and the writing core element are propelled forwardand thrust out of the opening of the front outer cylinder; and when therear outer cylinder is further rotated in the same direction, thewriting core element is propelled forward and thrust out of an openingon the front face of the mouthpiece.

(2) The writing instrument according to (1), wherein: the writinginstrument further comprises a connecting member; a flange shapedportion with a large diameter is arranged in the middle of theconnecting screw; a rear end face of the flange shaped portion isslidingly fitted to the front face of the rear outer cylinder; the frontouter cylinder is detachably connected to the connecting member; and theconnecting member is detachably connected to the connecting element.

(3) The writing instrument according to (1) or (2), wherein: in a firstrange starting from an arbitrary line in an axial direction on the innerface of the inner sheath, the refill sliding cam and the mouthpiecesliding cam respectively have first slopes; in a second range succeedingto the first range, the refill sliding cam has a perpendicular portionand the mouthpiece sliding cam has a sliding element fitting recess; inthe next third range, the refill sliding cam has a second slope and themouthpiece sliding cam has a perpendicular portion; in the next fourthrange, the refill sliding cam has a sliding element fitting recess; andin the next fifth range, the refill sliding cam and the mouthpiecesliding cam respectively have protrusions for restraining rotation.

(4) The writing instrument according to any one of (1) to (3), wherein:a resistant member is arranged on an outer face of the connectingelement such that the resistant member is slidingly contacted to therear outer cylinder.

(5) The writing instrument according to (4), wherein: the resistantmember is an O-ring.

Effects Attained by the Invention

The present invention can provide the rotating retractable writinginstrument, which can be constituted in the simpler way and can thrustthe mouthpiece and the writing core element smoothly to positions readyfor writing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline cross-sectional view illustrating an assembledstate by the whole parts of the writing instrument.

FIG. 2 is an outline cross-sectional view illustrating the rear outercylinder.

FIG. 3 is an outline cross-sectional view illustrating a head screw.

FIGS. 4A and 4B are views illustrating a structure of an inner sheath.

FIGS. 5A to 5D are cross-sectional views illustrating different portionsof the inner sheath.

FIG. 6 is developed views of a refill sliding cam and a mouthpiecesliding cam.

FIG. 7 is an outline cross-sectional view of a nut.

FIGS. 8A to 8F are views illustrating a refill sliding element.

FIGS. 9A to 9D are views illustrating a mouthpiece sliding element.

FIGS. 10A to 10C are cross-sectional views illustrating differentportions of the mouthpiece sliding element.

FIGS. 11A to 11E are views illustrating a connecting element.

FIG. 12 is an outline cross-sectional view of a connecting screw.

FIGS. 13A and 13B are views illustrating an inner cylinder.

FIG. 14 is an outline cross-sectional view of the mouthpiece.

FIG. 15 is an outline cross-sectional view of a front portion of thewriting instrument.

FIG. 16 is a front view of the writing core element.

FIGS. 17A to 17C are views illustrating working steps of the writinginstrument.

FIG. 18 is a view illustrating relations among the refill sliding cam,the mouthpiece sliding cam and a protrusion for restraining rotatingrange.

EXPLANATION OF REFERENCE CHARACTERS

-   1 writing instrument-   2 rear outer cylinder-   4 inner sheath-   6 refill sliding element-   7 mouthpiece sliding element-   8 connecting screw-   9 connecting element-   10 front outer cylinder-   11 inner cylinder-   12 mouthpiece-   13 writing core element-   42 refill sliding cam-   43 mouthpiece sliding cam-   45 protrusion for restraining rotating range

PREFERRED EMBODIMENT BY THE PRESENT INVENTION

The preferred embodiment by the present invention is explained asreferring to drawings.

Dimensions, materials, shapes and mutual arrangements of components arenot limited to descriptions in the present specification, unless theyare particularly specified in the specification.

Embodiment 1

FIG. 1 is the outline cross-sectional view illustrating the assembledstate by the whole parts of the rotating retractable writing instrument.As shown in FIG. 1, a writing instrument 1 comprises a rear outercylinder 2, a head screw 3 detachably attached to the rear outercylinder 2, an inner sheath 4 held in the rear outer cylinder 2, a nut 5held in the inner sheath 4, a refill sliding element 6 and a mouthpiecesliding element 7 slidably held in the inner sheath 4, a connectingscrew 8 as a connecting part slidably contacted to the rear outercylinder 2, a connecting element 9 detachably attached to the connectingscrew 8, a front outer cylinder 10 constituted by two parts detachablyattached to the connecting screw 8, an inner cylinder 11 slidably heldin the front outer cylinder 10, a mouthpiece 12 attached to the innercylinder 11, a writing core element 13 held in the inner cylinder 11 andin the mouthpiece sliding element 7 and return springs 14 arrangedbetween the front outer cylinder 10 and the inner cylinder 11, andbetween the writing core element 13 and the mouthpiece 12.

FIG. 2 is the outline cross-sectional view illustrating the rear outercylinder 2. As shown in FIG. 2, the rear outer cylinder is a cylindricalmember with open faces on both ends and an opening 21 is formed on itsrear end face. A protruded portion of the head screw 3 (which isexplained below) is inserted into the opening 21 on the rear end face,and a rim on a back face of the head screw 3 is slidingly contacted to arim on the rear end face of the rear outer cylinder 2. An arrangementwithout the head screw 3 is also possible, but the opening should not beformed on the rear end face of the rear outer cylinder 2.

A clip 22, which has been well known, may be detachably attached to therear end or an outer side face of the rear outer cylinder 2. In FIG. 2,the clip 22 is attached to the rear end of the rear outer cylinder 2. Inthis arrangement, a circular end of the clip 22 is held between the rearend of the rear outer cylinder 2 and the rim on the back face of thehead screw 3.

An inner face of the rear outer cylinder 2 is fitted to an outer face ofthe inner sheath 4. The front end face of the rear outer cylinder 2 isslidingly contacted to a rear end face of a large diameter portion ofthe connecting screw 8 (which will be explained below). The front endportion of the rear outer cylinder 2 is slidingly contacted to an outerside face of the connecting element 9 (which will be explained below)such that the rear outer cylinder 2 and the inner sheath 4 can berotated relatively to the connecting element 9.

FIG. 3 is the outline cross-sectional view illustrating the head screw3. As shown in FIG. 3, the head screw 3 has a protruded portion 31 sothat the head screw 3 shows a T-shaped cross section. The protrudedportion 31 is inserted into an opening on the rear end face of the innersheath 4 (which will be explained below). A screw groove 33 is formedaround on the outer face at the end of the protruded portion 31 so as tobe screwed in a screw groove formed around in the inner face at the rearend of a nut 5 (which will be explained below).

Engraved or holographic patterns may be formed on a surface 32 of thehead screw 3. The surface 32 may be covered with a resin coating. Aprotrusion having a hole for screwing a string may be formed on thesurface 32.

FIGS. 4A and 4B are views illustrating the structure of the inner sheath4. FIG. 4A is a plan view and FIG. 4B is a cross-sectional view cutalong a center line of FIG. 4A. FIGS. 5A to 5D are cross-sectional viewsof the inner sheath 4. FIG. 5A is a cross-sectional view cut along lineA-A in FIG. 4B. FIG. 5B is a cross-sectional view cut along line B-B inFIG. 4B. FIG. 5C is a cross-sectional view cut along line C-C in FIG.4B. FIG. 5D is a cross-sectional view cut along line D-D in FIG. 4B.

As shown in FIG. 4B, the inner sheath 4 is a cylindrical body with openfaces on both ends. As shown in FIG. 4A and FIG. 5A, a rear end portion41 is formed at one end of the sheath 4. A cross-section of the rear endportion 41 shows an annular ring shape partially cut by two parallelplanes. As shown in FIG. 1, the rear end portion 41 is protruded fromthe opening 21 of the rear outer cylinder 2 and the outer side face ofthe rear outer cylinder 2 is abrasively fitted to or adhesively fixed tothe inner face of the rear end portion 41. As a result the inner sheath4 unrotatably fitted to the rear outer cylinder 2.

As shown in FIG. 4A and FIG. 5B, straight grooves are formed on a rearportion of the sheath 4 in the axial direction.

The protruded portion 31 of the head screw 3 is inserted in an openingof the rear end portion 41 which is protruded from the opening 21 of therear outer cylinder 2, and the inner side face of the rear end portion41 and a base portion of the protruded portion 31 are abrasively fittedeach other. And a tip of the protruded portion 31 passes through therear end portion 41 of the inner sheath 4.

As shown in FIG. 4A and FIG. 5C, slits 44 are formed on a front portionof the sheath 4. Protruded portions formed on a rear outer face of theconnecting element 9 (which will be explained below) are held in theslits 44. As shown in FIG. 4A and FIG. 5D, a protrusion 45 forrestraining rotating range is formed at a front end of the sheath 4.

A refill sliding cam 42 is formed on the rear end portion of an innerface of the sheath 4 and a mouthpiece sliding cam 43 is formed on thefront end portion of the inner face of the sheath 4.

The refill sliding cam 42 and the mouthpiece sliding cam 43 will beexplained in detail below. FIG. 6 is developed diagrams of the refillsliding cam 42 and the mouthpiece sliding cam 43 formed on the innerface of the sheath 4.

Starting from an arbitrary point in a range from 0° to 180° the refillsliding cam 42 and the mouthpiece sliding cam 43 respectively have firstslopes 61, 62 with arbitrary inclinations in the axial direction of thesheath 4. Heights of the both slopes in the axial direction are nearlythe same.

The refill sliding cam 42 has a perpendicular portion 63 to the axialdirection starting from α₂ near 180° to α₃. The mouthpiece sliding cam43 has a sliding member fitting recess 64 in a range from β₃ to β₄. Therefill sliding cam 42 also has a slope 65 with an arbitrary inclinationin the axial direction in a range from α₃ to α₄. The mouthpiece slidingcam 43 has a perpendicular portion 66 to the axial direction at positionβ₄. The refill sliding cam 42 has a sliding member fitting recess 67 ata position α₅. Both refill sliding cam 42 and mouthpiece sliding cam 43respectively have protrusions 68, 69 for restraining rotation near 360°.Relations among angles α and β are as follows.

0<β₁<α₁<α₂<β₂<180°<β₃<α₃<β₄<α₄<α₅<360°

FIG. 7 is the outline cross-sectional view of the nut 5. As shown inFIG. 7 the nut 5 is a cylindrical body with open faces on both ends.

A screw groove 51 is formed around an inner face of its rear end. Thetip of the protruded portion 31 of the head screw 3 passes through therear end portion 41 of the inner sheath 4 and the screw groove 33 of theprotruded portion 31 is screwed in the screw groove 51 of the nut 5 asthe protruded portion 31 being inserted in the rear end portion 41 ofthe inner sheath 4. As a result, the nut 5 is detachably connected tothe head screw 3 so that the rear outer cylinder 2 and the inner sheath4 are held by the nut 5 and the head screw 3. In a state where the screwgroove 33 of the head screw 3 and the screw groove 51 of the nut 5 areconnected each other, the nut 5 and the head screw 3 cannot relativelybe moved each other. But when the connection between the screw groove 33and the screw groove 51 is loosened, the nut 5 and the head screw 3 canbe relatively rotated each other.

A rear portion of an outer face of the nut 5 is slidingly fitted to theinner face of the sheath 4. A diameter of the outer face of the nut 5 isnearly the same as a diameter of the inner face of the refill slidingelement 6 (which will be explained below), so that the nut 5 isslidingly fitted to the inner face of the refill sliding element 6.

In the present embodiment, the nut 5 is formed as a separate part fromthe sheath 4, but it is not limited to this arrangement. For example,the nut 5 may be integrated with the sheath 4.

FIGS. 8A to 8F are views illustrating the refill sliding element 6. FIG.8A is a plan view, FIG. 8B is a partial front view of FIG. 8A, FIG. 8Cis a front cross-sectional view of FIG. 8A, FIG. 8D is a bottom view,and FIGS. 8E and 8F are left and side views of the refill slidingelement 6.

As shown in FIG. 8C, the refill sliding element 6 is a cylindrical bodywith open faces on both ends. The rear end face of the refill slidingelement 6 is fitted to the inner sheath 4. An inner face of the refillsliding element 6 is slidingly fitted to the outer face of the nut 5 andan outer face of the refill sliding element 6 is slidingly fitted to theinner face of the inner sheath 4, so that the refill sliding element 6is held by the inner sheath 4 and the nut 5 slidably in the axialdirection but unmovably in the radial direction. The rear outer cylinder2, the inner sheath 4 and the nut 5 are rotatable relative to the refillsliding element 6.

A protruded portion 81 for sliding is formed on the outer face of therefill sliding element 6 in the axial direction. The protruded portion81 for sliding is fitted to the refill sliding cam 42 of the innersheath 4. On the front end face of the refill sliding element 6,protrusions 82 for fitting are protruded in the axial direction.Protruded portions 83 for fitting are formed on the outer face of therespective protrusions 82 for fitting. The protrusions 82 for fittingand protruded portions 83 for fitting are held in slits formed on a rearportion of the mouthpiece sliding element 7 (which will be explainedbelow).

Protruded portions 84 for restraining are formed on the front outer faceof the refill sliding element 6 for fitting to recesses formed in therear portion of the mouthpiece sliding element 7.

FIGS. 9A to 9D are views illustrating the mouthpiece sliding element 7.FIG. 9A is a plan view, FIG. 9B is a front cross-sectional view andFIGS. 9C, 9D are respectively a left side view and a right side view.FIGS. 10A to 10C are cross-sectional views illustrating differentportions of the mouthpiece sliding element in FIGS. 9A to 9D. FIG. 10Ais a cross-sectional view cut along line A-A in FIG. 9B, FIG. 10B is across-sectional view cut along line B-B in FIG. 9B and FIG. 10C is across-sectional view cut along line C-C in FIG. 9B.

As shown in FIG. 9B, the mouthpiece sliding element 7 is a cylindricalbody with open faces on both ends. As clearly shown in FIG. 10B, aprotruded portion 91 for sliding is formed on a rear portion of themouthpiece sliding element 7. The protruded portion 91 for sliding isfitted to the mouthpiece sliding cam 43 formed in the inner sheath 4.

Slits 92 are formed on the rear portion of the mouthpiece slidingelement 7 in the axial direction. The slits 92 hold the protrusions 82for fitting and protruded portions 83 for fitting of the refill slidingelement 6. In this way, the refill sliding element 6 is slidingly butunrotatably connected to the mouthpiece sliding element 7.

Hollows 93 for restraining are formed on the rear inner face of themouthpiece sliding element 7. The protruded portions 84 for restrainingof the refill sliding element 6 are fitted to hollows 93 such that therefill sliding element 6 is slidingly but unrotatably connected to themouthpiece sliding element 7.

Guides 94 are formed on the outer face of the mouthpiece sliding element7 from a front face of the protruded portion 91 for sliding to near thefront end of the mouthpiece sliding element 7. The guides 94 are held inguide rails formed on the rear inner face of the connecting element 9(which will be explained later). The front end of the mouthpiece slidingelement 7 fits a rear end face of the inner cylinder 11 (which will beexplained later).

FIGS. 11A to 11E are views illustrating the connecting element 9. FIG.11A is a plan view, FIG. 11B is a front cross-sectional view, FIG. 11Cis a right side view of FIG. 11B, FIG. 11D is a cross-sectional view cutalong line B-B in FIG. 11B and FIG. 11E is a cross-sectional view cutalong line C-C in FIG. 11B.

As shown in FIG. 11B, the connecting element 9 is a cylindrical bodywith open faces on both ends. A protruded portion 111 is formed aroundon a rear outer face of the connecting element 9. The protruded portion111 is held in the slits 44 of the inner sheath 4, so that the innersheath 4 is rotatably but unmovably in the axial direction connected tothe connecting element 9.

Guide rails 112 are formed on a rear inner face of the connectingelement 9. The guides 94 formed on the outer face of the mouthpiecesliding element 7 are held in the guide rails 112 such that themouthpiece sliding element 7 is slidably but unrotatably fitted to theconnecting element 9. The outer face of the mouthpiece sliding element 7is slidingly contacted to the inner face of the connecting element 9.

A flange shaped inner sheath fitting portion 113 is formed around in themiddle of the outer face of the connecting element 9. The front end faceof the protruded portion 45 for restraining rotating range formed on theinner sheath 4 is slidingly contacted to a rear face of the inner sheathfitting portion 113. A rotating position restraining member 114 isformed backward from the rear face of the inner sheath fitting portion113. A screw groove 115 is formed around on a front inner face of theconnecting element 9 so as to be screwed to a screw groove formed arounda rear outer face of the connecting screw (which will be explainedbelow).

The outer face of the connecting element 9 beginning from the rear faceof the inner sheath fitting portion 113, is slidingly contacted to theinner face of the inner sheath 4 and the front outer face of theconnecting element 9 is slidingly contacted to the inner face of therear outer cylinder 2, so that the rear outer cylinder 2 and the innersheath 4 are slidingly rotatable relative to the connecting element 9. Arotating range of the inner sheath 4 is restrained to a position wherethe protruded portion 45 for restraining rotating range is fitted to therotating position restraining member 114.

An O-ring holding groove 116 is formed around on the outer face of theconnecting element 9. A rubber O-ring as a resistant member is held inthe O-ring holding groove 116 and the outer face of the O-ring isslidingly contacted to the inner face of the rear outer cylinder 2. Dueto this arrangement, a friction force is generated between the outerface of the O-ring and the rear outer cylinder 2, so that appropriateresistance is added to the rotation of the inner sheath 4 and the rearouter cylinder 2.

The material for the O-ring is not limited to rubber, but any materialwhich can generate appropriate resistance may be employed. The shape ofthe O-ring is not specifically limited.

FIG. 12 is the outline cross-sectional view of the connecting screw 8.As shown in the drawing, the connecting screw 8 is a cylindrical bodyhaving a flange shaped portion 121 of a larger diameter on nearly itscenter and open faces on both ends. The outer face of the flange shapedportion 112 together with the front outer cylinder 10 (which will beexplained below) and the rear outer cylinder 2 forms an appearance ofthe writing instrument 1. The front side face of the flange shapedportion 112 is slidingly contacted to the rear end face of the frontouter cylinder 10. And the rear side face of the flange shaped portion112 is slidingly contacted to the front end face of the rear outercylinder 2.

A screw groove 122 is formed around on a rear outer face of theconnecting screw 8 so as to be screwed to the screw groove 115 formedaround on the front inner face of the connecting element 9. By thisarrangement, the connecting element 9 is detachably attached to theconnecting screw 8. An inner cylinder holding portion 123 is formed onthe rear inner face so as to be fitted to a rear end face of the innercylinder 11 (which will be explained below). The inner face of theconnecting screw 8 is slidingly contacted to the rear outer face of theinner cylinder 11.

A screw groove 124 is formed around on a front outer face of theconnecting screw 8 so as to be screwed to a screw groove formed around arear inner face of the front outer cylinder 10 (which will be explainedbelow).

FIGS. 13A and 13B are views illustrating the inner cylinder 11. FIG. 13Ais a cross-sectional view in the axial direction. FIG. 13B is across-sectional view cut along line A-A in FIG. 13A.

As shown in FIG. 13A, the inner cylinder 11 is a cylindrical body withopen faces on both ends. The rear end face of the inner cylinder 11 isfitted to the inner cylinder holding portion 123 of the connecting screw8. The rear end face is also fitted to the front end face of themouthpiece sliding element 7. As clearly shown in FIG. 13B, convexstrips 131 are formed on a rear inner face of the inner cylinder 11 at apredetermined pitch in the axial direction. The convex strips 131slidably support the writing core element 13.

A spring holding seat 132 is formed on a rear outer face of the innercylinder 11 so as to fit a rear end portion of a spring (which will beexplained below) for returning the mouthpiece sliding element. Thewriting core element 13 is inserted through the inner cylinder 11. Andthe inner cylinder 11 is inserted thorough the front outer cylinder 10.A screw groove 133 is formed around on the front outer face of the innercylinder 11 so as to be screwed to a screw groove formed on a rear innerface of the mouthpiece 12 (which will be explained below).

FIG. 14 is the outline cross-sectional view of the mouthpiece 12. Asshown in FIG. 14, the mouthpiece 12 is a hollow conical body with openfaces on both ends. A screw groove 141 is formed around on the rearinner face of the mouthpiece 12 so as to be screwed to the screw groove133 formed around the front outer face of the inner cylinder 11 and themouthpiece 12 is detachably connected to the inner cylinder 11.

A spring holding seat 142 is formed on a middle inner face of the innercylinder 11 so as to fit to the front end portion of a spring (whichwill be explained below) for returning the refill sliding element 6. Thewriting core element 13 can be thrust out of an opening 143 of themouthpiece 12.

The front outer cylinder 10 is explained as referring to FIG. 15. FIG.15 is the outline cross-sectional view of the front portion of thewriting instrument 1. As shown in FIG. 15, the front outer cylinder 10is a cylindrical body with open faces on both ends. The front outercylinder 10 consists of a cylindrical front end 151 and a grippingmember 152. A rear end face of the front cylinder 10 plays a role of aspring holding seat 153 for fitting a front end portion of a spring(which will be explained below) for returning the mouthpiece slidingelement.

The inner cylinder 11 and the mouthpiece 12 are inserted thorough thecylindrical front end 151. The mouthpiece 12 and the writing coreelement 13 can be thrust out of an opening on the front end of thecylindrical front end 151.

A screw groove 154 is formed around on a rear inner face of the grippingmember 152 for screwing to the screw groove 124 formed around on thefront outer face of the connecting screw 8, so that the front outercylinder 10 is detachably connected to the connecting screw 8. In afirmly connected state, the connecting screw 8 and the front outercylinder 10 can not be moved relatively to each other, but in a loosenedscrewed state the connecting screw 8 and the front outer cylinder 10 isrelatively rotatable relatively each other.

An inner face of the gripping member 152 is frictionally fitted to orabrasively fixed to an outer face of the cylindrical front end 151. Thegripping member 152 can be formed out of various materials, for example,elastic materials such as rubber and the like, wood, metal or the like.In the present embodiment, the front outer cylinder 10 consists of thecylindrical front end 151 and the gripping member 152. However, it maybe possible to integrate the cylindrical front end 151 and the grippingmember 152 into a one-pieced front outer cylinder.

Hereinafter, the springs for returning the refill sliding element 6, themouthpiece sliding element 7 and connecting screw 8 are explained asreferring to FIG. 15. As shown in FIG. 15, a spring 155 for returningthe mouthpiece sliding element is accommodated in an annular spaceformed between the inner face of the gripping member 152 of the frontouter cylinder 10 and also the inner face of the connecting screw 8, andthe outer face of the inner cylinder 11 such that the spring 155 extendsfrom the spring holding seat 153 of the cylindrical front end 151 to thespring holding seat 132 of the inner cylinder 11.

A spring 156 for returning the refill sliding element is accommodated inan annular space formed between the inner face of the mouthpiece 12 andalso the inner face of the inner cylinder 11, and an outer face of thewriting core element 13 such that the spring 156 extends from the springholding seat 142 of the mouthpiece 12 and a spring holding seat formedon an outer face of a cartridge of the writing core element 13 (whichwill be explained below).

In the present embodiment, coil springs are employed as the spring 155for returning the mouthpiece sliding element and the spring 156 forreturning the refill sliding element, but they are not limited to thecoil springs. Other elastic members may be also employable.

FIG. 16 is the front view of the writing core element 13. In thedrawing, the writing core element 13 is illustrated as a well-known ballpoint pen refill. The writing core element consists of a cartridge 161with open faces on both ends for accommodating ink, an end plug 162 tobe inserted and fitted in the rear end of the cartridge 161 and a tipmember (a chip portion) 163 of the ball point pen. The rear outer faceof the writing core element 13 is held in inner faces of the protrusions82 for fitting of the refill sliding element 6, and the rear end face ofthe writing core element 13 is fitted to the front end face of therefill sliding element 6. A spring holding seat 164 is formed on a frontouter face of the cartridge 161 of the writing core element 13 forfitting a rear end portion of the spring 156 for returning the refillsliding element.

In the present embodiment the ball point pen refill is explained as thewriting core element, but it is not limited to the ball point penrefill. A well-known automatic pencil mechanism may be employed as thewriting core element.

Hereinafter working steps of the writing instrument by the presentinvention are explained as referring to FIGS. 17A to 17C and FIG. 18.

FIGS. 17A to 17C are the views illustrating working steps of the writinginstrument 1. FIG. 18 is the developed views showing relations among therefill sliding cam 42, the mouthpiece sliding cam 43 and the protrudedportion 45 for restraining rotating range of the inner sheath. When thewriting instrument is not in use, the mouthpiece 12 is held at aposition backward a little from the front opened face of the front outercylinder 10 as shown in FIG. 17A. And the writing core element 13 isheld at a position backward a little from the opening 143 of themouthpiece 12.

In this state, the inner cylinder 11, the mouthpiece 12 connected to theinner cylinder 11 and the mouthpiece sliding element 7 are pressedbackward by the spring 155 for returning the mouthpiece sliding element.And the writing core element 13 and the refill sliding element 6, towhich the writing core element 13 is fitted, are pressed backward by thespring 156 for returning the refill sliding element.

When the rear outer cylinder 2 and the inner sheath 4 are rotated oneturn in one direction relative to the front outer cylinder 10 and theconnecting screw 8, the mouthpiece sliding element 7 is propelledforward against a backward pressure by the spring 155 for returning themouthpiece sliding element.

As shown in FIG. 18, when the outer cylinder 2 and the inner sheath 4are rotated one turn in one direction as keeping the mouthpiece 12 andthe writing core element 13 in an accommodated state, during a half turnfrom 0 to 180° the first slope 61 of the refill sliding cam 42 and theprotruded portion 81 for sliding of the refill sliding element 6 arefitted each other, so that the protruded portion 81 is slidingly movedforward as being pushed by the first slope 61. In the same way, thefirst slope 62 of the mouthpiece sliding cam 43 and the protrudedportion 91 for sliding of the mouthpiece sliding element 7 are fittedeach other, so that the protruded portion 91 is slidingly moved forwardas being pushed by the first slope 62. At a turning position of 180° theprotruded portion 91 for sliding of the mouthpiece sliding element 7 isfitted to the sliding member fitting recess 64.

Since the first slope 61 of the refill sliding cam 42 and the firstslope 62 of the mouthpiece sliding cam 43 have nearly the sameinclination and height, the refill sliding element 6 and mouthpiecesliding element 7 are slid forward by nearly the same distance.Therefore, a positional relation between the mouthpiece 12 and thewriting core element 13 is virtually unchanged before and after they areslid. By these sliding movements the mouthpiece sliding element 7 andthe refill sliding element 6 are moved to positions shown in FIG. 17B,so that the mouthpiece 12 and the writing core element 13 are thrust outof the front opening of the front outer cylinder 10.

When the outer cylinder 2 and the inner sheath 4 are rotated in the samedirection further, only the refill sliding element 6 is propelledforward against the pressure by the spring 156 for returning the refillsliding element.

In other words, as shown in FIG. 18, when the outer cylinder 2 and theinner sheath 4 are rotated in the same direction as keeping themouthpiece 12 and the writing core element 13 in a state being thrustout of the front opening of the front outer cylinder 10, during apartial turn from 180° to 270°, the second slope 65 of the refillsliding cam 42 and the protruded portion 81 for sliding of the refillsliding element 6 are fitted each other, so that the protruded portion81 for sliding of the refill sliding element 6 is slidingly movedforward as being pushed by the second slope 65. At a position of 270°the protruded portion 81 for sliding of the refill sliding element 6 isfitted to the sliding member fitting recess 67. On the other hand, sincethe protruded portion 91 for sliding of the mouthpiece sliding element 7and the perpendicular portion 66 of the mouthpiece sliding cam 43 arefitted together, the mouthpiece sliding element 7 is not slidingly movedforward.

In this way the chip portion 163 of the ball point pen of the writingcore element 13 reached to a thrust position out of the front endopening 143 of the mouthpiece 12 as shown in FIG. 17C.

The refill sliding cam 42 and the mouthpiece sliding cam 43 respectivelyhave the protrusions 68, 69 for restraining rotation, and theseprotrusions fit to the protruded portion 81 of the refill slidingelement 6 and the protruded portion 91 of the mouthpiece sliding element7 respectively, so that the rear outer cylinder 2 and the inner cylinder4 cannot be rotated beyond 270°. Since the protrusion 45 for restrainingrotating range of the inner sheath 4 fits to the rotating positionrestraining member 114 of the connecting element 9, further rotationbeyond 270° of the rear outer cylinder 2 and the inner cylinder 4 arealso restrained.

In order to accommodate the chip portion 163 of the ball pint pen of thewriting core element 13 and the mouthpiece 12 into the main body of thewriting instrument, the rear outer cylinder 2 and the inner sheath 4 arerotated in the reverse direction. In this way, pressures of the spring155 for returning the mouthpiece sliding element and the spring 156 forreturning the refill sliding element have the mouthpiece 12 and thewriting core element 13 being accommodated into the main body of thewriting instrument 1 by carrying out of the above-mentioned steps in thereverse order. The mouthpiece 12 and the writing core element 13 may beaccommodated into the main body of the writing instrument by othermechanical ways than by pressures of the springs.

In order to exchange the writing core element 13, the connecting element8 and the front outer cylinder 10 are separated from the rear outercylinder 2 after the connecting screw 8 and connecting element 9 areunscrewed. In this state, the writing core element 13 can be pulled outof the rear outer cylinder 2 by pulling forward the writing core element13 held in the rear outer cylinder 2.

Then a new writing core element 13 is inserted into the rear outercylinder 2 and the rear end face of the writing core element 13 isfitted to the front end face of the refill sliding element 6. Then theconnecting screw 8 and connecting element 9 are screwed together afterthe front outer cylinder 10 and the connecting screw 8 are fitted to therear outer cylinder 2. By these successive steps the writing coreelement 13 is exchanged.

1. A rotating retractable writing instrument comprising: a rear outercylinder with an open front face; an inner sheath unrotatablyaccommodated in said rear outer cylinder; and a front outer cylinderwith open faces on both ends, wherein: a mouthpiece and a writing coreelement can be thrust out of an opening formed on the front face of saidfront outer cylinder, said writing instrument further comprising: aprotrusion for restraining rotating range arranged on a front end faceof said inner sheath; and a refill sliding cam and a mouthpiece slidingcam formed on an inner face of said inner sheath, said writinginstrument further comprising: a refill sliding element and a mouthpiecesliding element accommodated in said inner sheath slidably in an axialdirection and unmovably in a radial direction; and protruded portionsfor sliding formed respectively on outer faces of said refill slidingelement and said mouthpiece sliding element; wherein: said protrudedportions for sliding are respectively fitted to said refill sliding camand said mouthpiece sliding cam; and said mouthpiece sliding element isslidably and unrotatably connected to said refill sliding element, saidwriting instrument further comprising: a connecting element connected tosaid inner sheath rotatably and unmovably in the axial direction; and arotating position restraining member arranged on an outer face of saidconnecting element for restraining a rotation of said inner sheath;wherein: said mouthpiece sliding element is slidably fitted to saidconnecting element, wherein: when said rear outer cylinder is rotated inone direction relative to said connecting element, said inner sheath isrotated in the same direction together with said rear outer cylinder sothat said mouthpiece and said writing core element are propelled forwardand thrust out of said opening of said front outer cylinder; and whensaid rear outer cylinder is further rotated in the same direction, saidwriting core element is propelled forward and thrust out of an openingon the front face of said mouthpiece.
 2. The writing instrumentaccording to claim 1, wherein: said writing instrument further comprisesa connecting member; a flange shaped portion with a large diameter isarranged in the middle of said connecting screw; a rear end face of saidflange shaped portion is slidingly fitted to the front face of said rearouter cylinder; said front outer cylinder is detachably connected tosaid connecting member; and said connecting member is detachablyconnected to said connecting element.
 3. The writing instrumentaccording to claim 1, wherein: in a first range starting from anarbitrary line in an axial direction on the inner face of said innersheath, said refill sliding cam and said mouthpiece sliding camrespectively have first slopes; in a second range succeeding to thefirst range, said refill sliding cam has a perpendicular portion andsaid mouthpiece sliding cam has a sliding element fitting recess; in thenext third range, said refill sliding cam has a second slope and saidmouthpiece sliding cam has a perpendicular portion; in the next fourthrange, said refill sliding cam has a sliding element fitting recess; andin the next fifth range, said refill sliding cam and said mouthpiecesliding cam respectively have protrusions for restraining rotation. 4.The writing instrument according to claim 1, wherein: a resistant memberis arranged on an outer face of said connecting element such that saidresistant member is slidingly contacted to said rear outer cylinder. 5.The writing instrument according to claim 4, wherein: said resistantmember is an O-ring.